Cai Gehao, Sun Bing, Zeng Sheng, Yang Peng, Zhang Jie
School of Civil Engineering, University of South China, Hengyang, China.
China Nuclear Construction Key Laboratory of High Performance Concrete, University of South China, Hengyang, China.
PLoS One. 2025 Jul 1;20(7):e0325279. doi: 10.1371/journal.pone.0325279. eCollection 2025.
This study investigates the influence of built-in studs on the bond behavior in recycled aggregate concrete-filled steel tube (RACFST) composite structures through push-out experiments. The effects of stud number, position, and rows on RACFST bond strength and steel tube surface strain are systematically analyzed. Furthermore, the bond-slip behavior evolution mechanism is examined, and a constitutive equation is established. A novel interfacial modeling approach is developed via secondary development of ABAQUS software to comprehensively simulate RACFST interfacial bond-slip behavior. The results demonstrate that insufficient stud quantity compromises interface integrity, reducing bond strength, while increased stud count enhances composite stiffness and bond performance. Studs positioned nearer the free end extend the natural bond length participating in shear resistance, thereby improving bond strength. Internal studs promote stress redistribution within the composite structure, significantly improving collaborative performance. The proposed constitutive equation shows good agreement with experimental results, and the developed interface program accurately captures bond-slip curve trends. These findings facilitate RACFST applications and provide guidance for shear stud arrangement in RACFST structures.
本研究通过推出试验，研究内置栓钉对再生混凝土填充钢管（RACFST）组合结构粘结性能的影响。系统分析了栓钉数量、位置和排数对RACFST粘结强度和钢管表面应变的影响。此外，研究了粘结-滑移行为的演化机制，并建立了本构方程。通过ABAQUS软件的二次开发，开发了一种新颖的界面建模方法，以全面模拟RACFST界面粘结-滑移行为。结果表明，栓钉数量不足会损害界面完整性，降低粘结强度，而增加栓钉数量可提高组合结构的刚度和粘结性能。靠近自由端的栓钉延长了参与抗剪的自然粘结长度，从而提高了粘结强度。内部栓钉促进了组合结构内的应力重新分布，显著提高了协同性能。所提出的本构方程与试验结果吻合良好，所开发的界面程序准确地捕捉了粘结-滑移曲线趋势。这些研究结果有助于RACFST的应用，并为RACFST结构中抗剪栓钉的布置提供指导。
